Sewing machine



R E. JOHNSON ETAL April 7, 1953 SEWING MACHINE Filed Jan. 24, 1951 31mm BillfY/ZE 07557190711 fiarlesfljssler Patented Apr. 7, 1953 SEWING MACHINE Ralph E. Johnson, Mountainside, and Charles A.

Kessler, Plainfield, N. J assignors toThe Singer Manufacturing Company, Elizabeth, N.'J.',

a corporation of New Jersey Application January 24, 1951, Serial N0.207,53l

1 Claim. (01. 112-4215) This invention relates to sewing machines and more particularly to a sewing machine which is adapted to be employed in the stitching of elastic material.

. The conventional lock-stitch sewing machine employs a throat-plate which is provided with a plurality of parallel feed-dog slots and a circular needle-receiving aperture positioned between a pair of such slots. Employed in conjunction with such a throat-plate is a, feed-dog having serrated arms which move within the slots and a presser-foot having a longitudinal needle-receiving slot. Experience has indicated that such a conventional sewing machine causes elastic cloth, such as nylon, to be unduly stretched during the stitch-setting operation due a the result that the finished article has a tendency topucker upon the completion of the stitching operation. 4

A primary object of the present invention is the provisionof a sewing machine which is capable of sewing elastic cloth, such as nylon, without causing the cloth to stretch during the stitching operation.

The foregoing object and others ancillary thereto have been attained by the provision of a novel throat-plate, feed-dog and presser-foot which, when applied to a conventional type sewing machine, cooperate together to feed elastic material past the stitching area of a sewing machine without causing the material to be unduly stretched to the end that the resulting stitched material will have no tendency to pucker.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawings Fig. 1 represents an end elevation, partly in section, of a stitch-forming and feeding mechanism of a sewing machine showing the improved mechanism.

, r 2 p a Fig. 2 represents a top plan view illustrating the sewing machine bed, throat-plate and feed-dog. .1 a

Fig. 3 represents a sectional view taken sub-1- stantially along the line 33 of Fig. 1.

Fig. 4 represents a fragmentary longitudinal sectional view through a portion of the presserfoot, throat-plate and feed-dog of the present mechanism. a

Fig. 5 represents a fragmentary sectional view taken substantially along the line 5-5 of Fig. 1. In the embodiment of the invention selected for illustration, my improved mechanism is shown applied to a sewing machine having a bed l0 and a head ll. Journaled below the; bed I0 is a rotary loop-taker l2 and the usual feedrockers l3 and 14 which impart a four-motion movement to a feed-dog l5 through the medium of a feed-bar l6; in the usual and well-known manner. Mounted upon the bed I0 is a throatplate I! formed with an aperture I8 through which the feed-dog l5 operates. 1 I Journaled for reciprocatory movement infthe head II is a needle-bar l9 carrying an eyepointed needle 20. Also journaled for right line up and down movement in the head ll isthe usual spring depressed presser-bar 2| having secured thereto, by means of a screw 22, a presser-foot shank 23. Pivotally mounted upon the presser-foot shank 23, by means of a crosspin 24, is a pressure-foot generally designated by the numeral 25, which presser-foot cooperates with the feed-dog [5 in the feeding of the work 26 to and past the stitching area. For a more complete and detailed description of the sewing machine mechanism, reference may be had to the patent of Kaier, No. 2,206,285, dated July 2, 1940.

As hereinabove noted, a conventional sewing machine causes elastic work material to be unduly stretched during the stitch-setting operation due to the fact that the feed-dog functions to advance the work-material over the throatplate and past the needle-receiving aperture at the same time that the take-up mechanism sets the stitch. These two actions occurring simultaneously cause the needle-thread to exert a pull on the work-material in a direction opposite to the direction of feed and thus the elastic cloth is stretched with a result that the finished article has a tendency to pucker as the material relaxes. This action may be better understood by referring to Fig. 1 wherein the work-material is designated by the numeral 26 and the needle 20 is illustrated as provided with needle-thread designated by the numeral 27, while the bobbin thread is designated by the numeral 28. Durin the stitch-setting operation, the usual feed-dog functions to advance the work 26 over the throatplate and past the stitching area in a, left-hand direction as viewed in Fig. 1, while at the same time thetake-up' mechanism sets the stitch by pulling upwardly on theneedle thread 21. These two actions occurring simultaneously cause the needle-thread to pull upwardly and away from.

the work material 26 in a right-hand direction which is directly opposed to the feeding action which urges the work-materialxin a. left-hand direction, and thus the elastic clothis stretched.

the above noted shortcoming in a conventional sewing machine.

The present feed-dog, generally designated by the numeral I5, is "provided intermediatethe ends of its teeth-carrying bridge elementsZS; 29 with a horizontally disposed platform 30 which is provided with an elongated needle-receiving slot 3|. -The upper surface of this platforrn-30 isdisposed flush with the top portions of the feed-dog teeth 32 which surround it.

The present throat-plate l1 differs from a conventional unit in that it is provided with no needl'e receiving aperture and in lieu thereof it is formed with a large central opening'lfi which is adapted to receive the above noted feed-dog platform 30 as well as the bridge elements 29; 29 as the feed-dog advances the work over the throat-plate. At opposite ends of the throatplate opening. I8 there are provided finger elements 33, 33 which extend between the various feed-dog bridge elements in order to support the work during the feeding operations.

The present presser-foot 25 differs from a conventional unit in that the usual open-ended needle-receiving slot has been replaced by a circular needle-receiving aperture- 34.

It is thefunction of the present feed-dog to have its platform member 30 clamp the work being stitched against the presser-foot 25 in the area directly surrounding the needle-thread 2? so that any relativelateral motion between the Work 26 and the thread 21 will not tend to stretch the. work.- By referring particularly to Figs. 1,

The present sewing ma 4 and 5 it will be appreciated that the'fee'd-dog platform 30 not only completely surrounds the work in the area directly surrounding the needle- 4 thread, but at the same time it looks the needlethread itself between the platform and the presser-foot thereby to prevent the thread from stretching the work during the stitch-setting operation. Since the usual presser-foot slot has been eliminated and in lieu thereof the presserfoot has been provided with a: circuIa-r'aperture 34, the Work may be rigidly clamped between the presser-foot and the feed-dog platform 30 and thus the needle-thread has little opportunity tocause portions of the material to be stretched in a lateral direction.

Having thus set forth the nature of the invention, what we claim herein is:

A sewing machine for sewing elastic work material and having, in combination, a flat apertured work-support, a reciprocatory needle, a presser-foot spring-biased toward said worksupport and having a needle-receiving aperture therein, said needle and said presser-foot each being disposed at one side of and being confined for rectilinear movements toward and from the flat surface of said work-support, a feed-dog disposed at the other side of said work-support and adapted for movements within the worksupport aperture and longitudinally ,of said presser-foot thereby to cooperate with said latter element in the feeding of work material over said Work-support, a platform member having a flat upper surface and an elongated needlereceiving aperture therein and carried by 'said feed-dog for cooperating with said presser-foot in clamping the work material between the flat upper surface and said presser-foot in an .area surrounding the puncture made in thework by said needle, serrated Work-feeding elements carried by said feed-dog and having their upper surfaces disposed in a substantially coplaner relation with the flat surface of said platform, and means for imparting work-feeding movements to said f eed-dog.

RALPH E. 'JOHNSON.- CHARLES A. KESSLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 7 Date 1,266,837 McNeil May 21, 1918 2,369,118 Cumfer Feb. 13, 1945 

